Trivia

In the pilot episode, in the beginning when we see Riggs's wife, Miranda, wave to the next-door neighbor watering his lawn, the house behind him is the house the Murtaughs lived in from the Lethal Weapon films.

Unlike typical, dramatized depictions in film and TV, the technique Riggs uses to kick down doors by turning his back and kicking the door behind him--known as the mule kick--is often preferred and physiologically accepted as a stronger and more reliable method.

In the last episode of Season 1 during the graduation, one name is called out, Michael Waynes Kyle, which is a play on Damon's character from My Wife and Kids, Michael Kyle.

In April 2018 Deadline Hollywood's Nellie Andreeva reported that negotiations for the show's third season renewal were being complicated by an ongoing problem with Clayne Crawford's on-set behavior. Andreeva reported that Crawford (Martin Riggs) had been repeatedly reprimanded for creating an emotionally abusive and hostile work environment and that the issue had "escalated to a point where other actors as well as crew on Lethal Weapon would feel uncomfortable being on set with him." Andreeva wrote that because past disciplinary action had not resulted in Crawford remediating his behavior, the showrunners were taking the very unusual step of considering the recasting of his role. After its publication in Deadline Hollywood, this story was picked up and republished in many other entertainment news outlets, including TV Guide, Vulture, TV Line, and others. In May 2018, Crawford was replaced by Seann William Scott in a new character, former Navy SEAL Wesley Cole.

Advertisements for this series credited Clayne Crawford as "Introducing Clayne Crawford" (a credit usually reserved for actors making a debut) even though Crawford had his first onscreen credit in 1997 (in an episode of "Buffy the Vampire Slayer") and has multiple credits per year, every year, since the early 2000s.